It is known that many diseases known to human and veterinary medicine are carried by pathogenic microorganisms in the bloodstream, including viruses, Rickettsiae, bacteria, fungi, and parasitic protozoa and worms. Most of these diseases, are treated by oral ingestion or subcutaneous administration of chemical or biological drugs which destroy or deactivate the pathogenic microorganisms. However, dosages of the effective drugs must be limited because of the danger of undesirable secondary effects. Even at recommended dosages many drugs produce adverse side effects.
In addition, there are known agents which have the capacity to kill or deactivate pathogenic foreign microorganisms in vitro, but which are not used therapeutically because they are known to have toxic, or other adverse effects.
It is also known that infection is sometimes transmitted to the recipient of a whole blood or plasma transfusion from pathogenic organisms in the blood of the donor.